Heikki Linnakangas <hlinnaka@iki.fi> writes:
> Vacuum doesn't zero out the free space between lower and upper,
It does now ;-)
> How about adding a flag to XLogRecData to indicate if the space between
> pd_lower and pd_upper is meaningful or not? The XLogInsert caller probably
> knows that. That way you could completely skip over the free space if
> it's not meaningful, saving even more cycles.
Hmm ... that might not be a bad idea. As far as I can think offhand,
all the XLogInsert callers know very well what type of page they are
working with, so they would always be able to set such a flag correctly.
Would this be institutionalizing a particular approach to data
compression in the XLogInsert API, though?
regards, tom lane